Telephony.



M. L. JOHNSON.

TELEPHONY. APPLICATION FILED APR, 5, 1913- 1,147,025. Patented July 20,1915.

3 SHEETS-SHEET 1.

WI TNE S S E S INVENT on W Moa ron L. {JOHNSON BY 7 ATTORNE M. L.JOHNSON.

TELEPHONY.

APPLICATION FILED APR-5,1913.

1,147,025. Patented July 20, 1915.

3 SHEETS-SHEET 2.

INVEN T OR G u a MORTON. JOHNSON BY @21 ZZZ /Z% W ATT ORN EY WITNESSESCOLUMBIA PLANGORAPH co.,wAslllNuToN D c M. L. JOHNSON.

TELEPHONY.

APPLICATION FILED APR-5.1913.

1,147,025. Patented July 20, 1915.

w 3 SHEETS-SHEET 3.

FIG. 3

WITNESSES I INV'ENTOR & MORTONLIJOHNSON ATTORNEY COLUMBIA PLANOGRAPH c0WASHINGTON. D. c.

invrrnn STATES PATENT orrrcn.

MORTON L. JOHNSON, or oHIcAso, ILLINOIS, ASSIGNOR, BY ivInsNEASSIGNMENTS, To FRANK 13. 000 COMPANY, or CHICAGO, ILLINoIs, ACORPORATION or ILLINOIs.

TELEPHONY.

Specification of Letters Patent.

Patented July 20, 1915.

f Application filed A ri15,1913. s iia1Na75ao2a T whom it may concern aBe itknown that I, MORTO L. J HNSON, citizen of the United States,residing at Chicago,cin the-county of Cook andState of Illinois, haveinvented a certain new and useful Improvement in Telephony, of which thefollowing is a full, clear, concise, and exact description, referencebeing had to g the accompanying drawings, forming a part of thisspecification.

The invention has for one of its objects the provision of meanscontrolled by each selector switch which is the first to select aresponsive device'for holding a succeeding responsive device huntingselector switch in position to connect the SL1TIBIQSPOIIJSIVG devicewith the calling line operatingsuch succeeding. selector switch andoperator .con-

trolled vmeans for freeing the selected responsive device from the firstselector switch and'bringing it into connection with the sec ondselector switch and thereby with the calling line'operating the secondselector switch.

The invention has for another of its obects the provision of a group oflnk connectors at the/exchange for each operator to whose use itisadapted in connecting calling I and called lines, signal devlces forthellnk connectors of each. group, and means governed by equipment ofthe link connectors for causing such s gnal devices to operate whenthelrlink connectors are idle and to restore the signal devices when theirlink connectors are taken for use.

I will explain myinvention more fullyby reference to the accompanyingdrawings showing the preferred embodiment thereof and in which Figure isa very view illustrating, in simple form, the essential features of theinvention as they are preferably embodied; and Figs. 2 and 3,

taken collectively end to end with the discontinued conductors at .theright hand end of Fig. 2 in alinement with the discontinued conductorsat the left hand of Fig. 3, illustratethe preferred embodiment of the invention in diagrammatic detail.

Like parts are indicated by similarcharacters of reference throughoutthe different figures.

Referring first more particularly. to Fig. 1, I have there indicated twosubscribers stations 120 and 190 each having a selector general.diagrammatic switch A, B individual to its line but to which individualselector switches the invention is not to be limited. These selectorswitches have wipers which move over waiting-contacts that pertain totelephone line extensions C, D which are peculiar to calling lines andare included in connections between calling and called subscribers onlyat the calling line ends of such connections. There are preferably fiftyextensions C or D apportioned to the use of each operator and theextensions of each operators group are each provided with multipledwaiting contacts distributed among the switches of such operator. Thewipers of the switches E or F, selected for use by the operator, aremoved by operator controlled means over the waiting contact terminals ofthe calling line extensions, these switches being inclividual to linkconnectors whose connecting ends are here shown as terminating inconnecting' plugs G, the plugs G belonging to switches-E being at oneoperators position and the plugs G pertaining to the switches F being atanother operators position, there being desirably twenty five such plugsto each operators position and, of course, as many switches. The callingline extensions C, D are here shown as being divided into groups eachgroup being individual to an operators position and the selectorswitches A, B, in additionto selecting idle extensions C, D, will alsoselect the corresponding calling line operated operators responsivedevice which may be in the form of a signal lamp H or an operatorstelephone I, or both of these classes of-devices. When a callingsubscriber selects an idle calling line extension and the responsivedevice peculiar to the operators position to which the selectedextension belongs, the operator will select an idle link connector forjoining the calling line with the desired line and will cause theoperation of the switch E or F by means of a keyK individual to such.switch and the link connector having such switch to connect thecorresponding connecting plug G with the calling line.- The operatorwill complete the connection by inserting the plug G that has becomeconnected with the calling line into a jack L of the called linemultipled in her position. The responsive device I, is provided with tworelays M either of which, when energized, renders the responsive deviceI unselectable. The se- I lector switch first operating to energizeeither relay M connects the responsive device I with the calling line ofsuch switch, there being means (not indicated in Fig. 1) whereby asecond hunting selector switch may be arrested in association with thesecond relay M in readiness to connect the previously selectedresponsive device I with the second calling line when the responsivedevice has been freed by the operator when the plug G has becomeconnected with the first calling line, relay mechanism N, operatorcontrolled, performing this latter function.

Each link connector having a plug Gr also has a signal device 0individual thereto. \Vhen a link connector is taken for use theoperators relay P individual thereto efl'aces the associate signal at 0through the intermediation of a switching device Q, whose motor magnet Ris operated whenever a relay P is energized. A switching device Sgoverned by an operators key T may occupy one position so that but onesignal lamp 0 may be displayed at a time at one position irrespective ofthe number of idle links at such position or so that there may be asmany signals displayed at O as there are idle links individual thereto.As the system is equipped the link connectors may be idle though theirplugs G are inserted in jacks of lines at whose substations thereceivers have been restired to their switch hooks.

Referring now more particularly to Figs. 2 and 3, I have shown wellknown equipment at telephone stations 120 and 190, the equipment at eachstation including a telephone receiver switch hook 1, a telephonereceiver 2, a telephone transmitter 3, a call hell 4, and a condenser 5,the switch hook having a normal'contact for connecting the associatebell and condenser 5 in bridge of its line and an alternate contact forconnecting the telephone transmitter 3 in bridge of its line, thereceiver being in a closed local secondary circuit in inductive relationto the transmitter circuit. When a subscriber, say at station 120,initiates a call he removes his telephone receiver from its switch hookto engage the switch hook with its alternate contact whereby a circuitis established which is traceable from the upper grounded coil of thedifierential cutoif relay 6, the intermediate armature switch of theswitching relay 7 and its normal contact, both sides of the calling lineby way of the transmitter bridge at the calling station, the lowerarmature switch of the switching relay 7 and its normal contact, thelower winding of the cutoff relay 6, the line relay 8, to the groundedcommon battery 9. The armature switch of the line relay 8 is nowattracted to establish a circuit traceable from this grounded armatureswitch of this relay, the contact engaged by this switch, the motormagnet 10, the circuit interrupter 11, to the grounded common battery 9.The motor magnet lOsteps the wipers 12, 13, 14 of the selector switch Aof the calling line around until the wiper 14L engages a contact that isconnected with the grounded battery 9, whereupon circuit is establishedtraceable from the grounded battery 9, the armature switch of relay 15and its normal contact, the armature switch immediately above thewinding of magnet N, the contact engaged by the wiper 14, the armatureof motor magnet 10 and its contact, the winding of relay 7 to ground.The relay 7 establishes a locking circuit for itself traceable from itsgrounded terminal through its winding, its intermediate armature switchof the left hand alternate contact of this armature switch, both sidesof the calling line, the lower armature switch of relay 7, the alternatecontact of this armature switch, the wiper 13, the upper intermediatearmature switch of relay N and its normal follow-up contact, the relay16, the relay 15, to the common grounded battery 9. The circuit for theline relay 8 is now opened at the normal contacts of the two lowerarmature switches of relay 7 whereby the armature switch of relay 8 isreleased to open the circuit for motor magnet permitting the wipers 12,13, 14 to remain at rest. The uppermost armature switch of relay 7 isgrounded through a common resistance 17 and the common grounded battery9 so as to place battery in connection with the tip line springs of thejacks L pertaining to the calling lines to make the calling line busy.The relay 15 is now energized to cause its armature to engage itsalternate contacts to establish circuits through the calling signal orresponsive device H to attract the selected operators attention or forpurposes of supervision and through the relay M to connect the selectedoperators telephone I with the calling line.

The circuit for the element H is traceable directly to the groimdedbattery 9 connected with the armature switch of relay 15. The circuitfor the relay M is traceable from the grounded battery 9, the armatureswitch of relay 15, the right hand alternate contact of this armatureswitch, the winding of relay M, the lowermost armature switch of thecompanion relay M and the normal contact of this armature switch toground. The first relay M is energized to attract this armature switch,the two upper most armature switches serving to connect the operatorstelephone in bridge of the selected extension C and consequently inbridge of the calling line whereupon conversation may be held betweenthe calling subscriber and the selected operator. At this point it maybe well to mention the equipment by which the selected responsive deviceI is held for connection ployed ringing current generator, the righthand pair of contacts ofthe depressed key, the normally closed contactsof the remaining keys that happen to be to the right of the depressedkey, the winding of relay 33, the intermediate armature switch of relay28 and its alternate contact, the sleeve of the employed plug G, thesleeve line spring of the jack receiving this plug, the armature switchof the called line cutofi' relay 6 and its alternate contact, thelowermost armature switch of the called line switching relay 7, and itsnormal contact, the bell at the called station, the intermediatearmature switch of said relay 7, the normal contact of this armatureswitch, the tip spring of the'jack L receiving the plug G, the tip of 1this plug, the top armature switch of relay 28 and its alternatecontact, the primary test tone producing coil 34:, to the groundedbattery 9. Current finding path fromthe bat tery 9 through coil 34traverses the upper grounded winding of the called subscribers cutoffrelay 6 to energize this relay to attract its armature into engagementwith its alternate contact to complete the sleeve side of the calledline and also to open the circuit of the line relay 8 at the normalcontact of the armature switch of relay 6 to'open the circuit of thecalled subscribers motor magnet 10 so that when the called subscriberresponds he will not set his selector switch B into operation.

l/Vhen the relay 29 is energized its upper armature switch establishes acircuit by way of its right hand contact that includes the upperarmature switch of relay 30 and its contact, the motor magnet 35, theinterrupter 36, and the grounded battery 9. The motor magnet 35 willdrive the wipers 37, 38, 39 around until the wiper 39 encounters aWaiting contact that isconnected with battery and is free of directground connection, this being a condition that is imposed by theoperator upon a calling line extension that has become connected withthe calling line and which is to be connected with the employed plug G.The means shown for placing this condition upon the waiting contact ofthe calling line to be engaged by the wiper 39 happens to be anoperators key K.

that causes the closure of the circuit of the relay 25 momentarily. Therelay 25 momentarily closes a circuit traceable from this groundedarmature switch, the lower contact of this switch, the relay 4:0, to thegrounded battery 9. The relay 40 establishes a locking circuit foritself traceable from the grounded battery 9, the lower armature switchof relay 40, the contact of this switch, the left hand alternate contactof the bottom armaa ture switch of the operated relay M, to ground byway of said armature switch. The upper armature switch of relay 4Oestablishes circuit traceable from the grounded battery 9,

contact (the battery connection thus established upon this contact beingestablished by the operator for the purpose of arresting the wiper 39 inengagement with this Contact),

the windingof sluggishly operating relay 30, the armature switch ofmotor magnet 35, and ts contact, to ground. The lower arma-= ture switchof relay 30-is attracted to leave its normal contact to open thelockingcir-j cuit for the relay 29 to releaseithis relay, the upper armatureswitch of relay 29 opening the circuit of the motor magnet '35 as theright hand contact of this, armature switch whereby the wipers 37, 3Sand 39 are permitted to remain in the positions to which they have beenbrought when the wiper 39 is in engagement with the waiting contact uponwhich battery was placed by the operator at the armature switch of relay25. The lower armature switch of energized relay 30 establishes acircuit traceable from the grounded battery 9, this armature switch, thealternate contact of this switch, the winding of relay P to ground. Therelay P established a locking circuit for itself trace-, able from itsgrounded winding, through the armature switch of relay 41 and its lefthand contact, the resistance 42, to the grounded battery 9, the relay Phaving established a circuit for the relay 4C1 traceable from thegrounded battery 9, the winding of relay 41, the armature switchimmediately below the winding of relay P, the contact engaged by thisarmature switch, the wiper 38, the contact of the employed calling lineex tension engaged by this wiper, the upper intermediate armature switchof relay N,-

the alternate contact of this armature switch, the wiper 13 of thecalling line, the waiting contact engaged by this wiper, theme byobvious connections over-both sides of the calling line to theintermediate armature switch of the calling line switching relay 7, theleft hand alternate contact of this armature switch to said relay 7which is grounded, the circuit thus traced being possible owing to theenergization of the relay N previously traced through the wiper 39, therelay N having established a locking circuit for itself traceable fromthe grounded battery 9, the bottom armature switch of this relay, thecontact of this armature switch, the winding of relay N, the waitingcontact engaged by the wiper 39, said wiper 39, the next to the bottomarmature switch of relay P, the contact of this armature switch,'toground. The sluggish relay 41 is provided for maintaining the batterycir cuit for switching relay 7 while relays N and P are being operated.Whenrelay is energized it opens" the circuit for the associate relays 15and 16 at neXtfto the top armature switch of relay N and the normalfollow-up contact of this switchwhereupon relay 15 releases itsassociate magnetM to free the previously selected operators responsivedevice or telephone I.

The locking circuit for relay 40 is opened by the released relay M atits bottom armature switch and its left hand alternate contact wherebytheselected operators equipment is restored to selectable condition withregardto another calling line. The calling subscriber will know that thecalled party is being signaled owing to the transmission, of ringingcurrentifrom the coil 34 to the coil 43, the secondary circuitbeingtraceable from ground, the common battery 9, the secondary coil 43, therelay 44 (which is not energized by the"induced current), the condenser45, the armature switch immediately below the relay P and its contact,the wiper 38, thence by obvious connections to and through the callingsubscribers receiver. When the called subscriber responds he substitutesa low resistance telephone bridge for the high resistance bell" bridgepermitting sufficient current to flow from the employed ringinggenerator through the relay 33 to energize this relay toopen the lockingcircuitiof the magnet 28 at the normal contact of the armatureswitch ofrelay 33 whereby the relay 28 is deenergized to permit its two upperarmature switches to engage their normal contacts; When cir cuit throughrelay 33 is completed it momentarily establishes circuit at thealternate contact of this armature switch through the sluggishlyoperating relay 46, the armature switch of relay 46 momentarilyconnecting the battery 9 with the tip of the employed plug G so as toprevent faulty operation of the called subscribers cutofi relay 6. Acircuit isestablished through the relay 44 traceable from the groundedbattery 9, the secondary coil 43, the relay 44, the mid dle armatureswitch of relay P and its contact, the lower intermediate armaturesubscribers are through conversation they will restore their receiversupon their switch hooks and if the called subscriber, restores hisreceiver first relay 44 will be deenergi'zed owing to the breakage ofthe circuit at the called station, whereupon a momentary circuit isestablished traceable from the grounded battery 9, the resistance 42,the armature switch of relay 44 and its normal contact, the armatureswitch of sluggishly operating relay 47 and its normal follow-upcontact, the alternate contact of this armature switch, the relay 32, toground, the connections including the armature switch of relay 47 andits two contacts occurring during the release of this armature switch,circuit for the relay 47 having'previously been established by way ofthe right hand alternate contact of the armature switch of relay 44. Alocking circuit is established for the relay 32 traceable from ground,the winding of this relay, the bottom armature switch of relay 32 andits contact, the armature switch of relay 41 and its right hand contact,the resistance 42, to the grounded battery 9. When relay 32 is energizedits intermediate armature switches engage their alternate contacts toinclude the secondary coil 48 in bridge of the calling line, a test tonebeing induced inthis coil from the primary coil 49 that is included in alocal circuit with an interrupter 50 whereby the calling subscriber isinformed that the called subscriber has replaced his receiver upon itsswitch hook. The called subscriber is now placed inicontrol of his ownline relay 8 owing to the deenergization of his cutoif relay 6. At thisstage of the operation the talking strands leading tothe plug G arebroken at the intermediate armature switches of relay 32 so as torelieve the portions of the talking strands intervening between thisplug and these armature switches free of bridge connections whereby thepreivously busy and now free called line may be called over a newconnection, the plug G being permitted to remain in the jack of thecalled line. When the calling subscriber restores his receiver upon hisswitch hook circuit for his relay 7 and the relay 41 is opened at thealternate contact of the calling subscribers switch hook, whereupontheir armature-switches are restored to normal, the wipers 12, 13 and 14remaining in engagement with the contacts that they previously came incontact with, this being possible owing to the separation of the wipers12, 13 and 14 from the calling line equipment at the lower armatureswitches of relay 7 and the armature switch of relay 10.

The wipers 12, 13 and 14 of the calling line selector switches do not,in the embodimentof the invention herein shown, restore to normal butcontinue to rotate in a single direction only and upon release theysimplyremain in engagement with the contacts into connection. This is avery advantageous feature as the equipment of the selector switch issimplified and the wipers are enabled to continue their rotation untilthey engage idle waiting contacts, such rotation being continued if itshould happen that all of the waiting contacts are busy and lastinguntil a set is free. hen the calling subscriber restores his telephone"upon his switch hook the relay 4:1 is deenergized to open the lockingcircuit for the relay 32 at the right hand alternate contact of thearmature switch of relay ll. A circuit path for relay P is opened at theleft hand contact of the armature switch of relay l1 controlled by thecalling subscriber and another and remaining circuit path for this relayP is opened at the left hand alternate contact of the armature switch ofrelay 4A, which relay is deenergized with the called subscriber restoreshis receiver upon its switch hook. Relay P is thus under joint controlof the calling and called subscriber when both subscribers have restoredtheir receivers upon their switch hooks this relay P is deenergized torelease its armature switches, the three upper armature switches of thisrelay P being restored to normal to disconnect the wipers 37, and 38from the link at the relay P and also to disconnect the plug G from thewipers 37 and 38 and armature switches of relay P whereby the wipers 3738 and 39 and the plug G are freed from all link connector bridges sothat said plug G may remain, if desired, in the jack in which it wasplaced instead of being withdrawn by the operator when connectionbetween subscribers is through.

Assuming that the desired station 190 is busy, that is that the receiveris free of its hook at this station, the plug G having been inserted inthe jack'of the desired line, an operation which occurs without anytesting, a depression of a ringing key K will not cause the impressionof signaling current upon the line owing to the energization of therelay 27 which is energized by a circuit including the calling line andthe transmitter bridge at the called station. If the desired line is inthe act of being called by another operator and the telephone receiverat the station of the desired line is still upon its switch hook therelay 27 would also be energized as a consequence of a circuit traceablefrom the grounded battery 9, the primary winding 34: of the linkconnector employed by the operator previously calling the desired line,the uppermost armature switch of relay 28 of the operator alreadysignaling the desired line, the alternate contact of the top armatureswitch of the relay 28 belonging to the operator first signaling thedesired line, the tip of the associate plug G, the tip spring of thejack engaging this plug, to the tip spring of the jack engaged by theplug G employed by the operator second to seek the desired'line, the toparmature switch of the relay 28 of this second operator, the normalfollow-up contact of this armature switch, the relay 27, the upperarmature switch of relay 26 to ground by way of the right hand contactof this armature. Relay 26 having previously been momentarily energized,cooperates, when thus momentarily energized, with the energized relay 27to establish a circuit traceable from the grounded battery 9, theresistance 31, the lower armature switch of relay 29, the left handcontact of this armature switch, the lower armature switch of relay 26the contact of this armature switch, the armature switch of relay 27 andits alternate contact, the winding of relay 32, to ground. The relay 32now establishes a locking circuit for itself traceable from its groundedcoil to its lowermost armature switch and contact, the lower armatureswitch of relay 29 and its right hand contact, the resistance 31, to thegrounded battery 9. When the relay 29 deenergized as previouslydescribed the battery connection dropped by the lower armature switch ofrelay 29, is replaced at the right hand contact of the armature switchof relay 41 The interme diate arI'nature switches of relay 32 energizedunder the conditions just described,

causes a busy tone tobe transferred by the elements 48 and 49. Thecalling subscriber, upon connecting this busy tone to indicate that thedesired line is busy, will restore his telephone upon its switch hook torelease relays ll and 7 to restore the line equipment and the linkconnector equipment to idle condition. The plug G is freed from bridgeconnections when the relay 32 is energized so that the condition of thedesired line is not modified by the equipment of an operator seekingconnection therewith while a preceding operator is seeking or hassecured connection therewith, the calling subscriber taking no part inthis result.

WVhen the connection between subscribers has been broken the employedswitchE remains in engagement with the contacts in connection with whichit was previously relay P, the motor magnet R, the interrupter S and thegrounded battery 9, the motor magnet R thereupon stepping the shaft Qaround step by step until the wiper 50 of the left hand switch Q becomesengaged with a succeeding ungrounded. waiting contact pertaining to anidle link connector. Wiper 51 moves together with wiper 50 andestablishes a circuit for the lamp 0 pertaining to the idle linkconnector that has become associated with the wiper 50, the similarlypositioned waiting contacts of the wipers pertaining to the same linkconnectors, there being as many waiting contacts as there are linkconnectors in an operators group. If it is desired to have all the lampsO of idle link connectors lighted, switch elements 52 individual to thenormal contacts of the bottom armature switches of relays P andindividual to the different link connectors are brought into connectionwith contacts that are included in the signaling circuits, there beingas many switches 52 as there are links in an operators position and allof the switches being adapted for simultaneous engagement with theircontacts through the agency of a magnet 53 controlled by an operatorspush button T. To prevent the lamps from flashing while the wiper. 50 isstepped around the motor magnet R closes circuit through a sluggishlyoperating relay 54 whose right hand armature switch opens the circuit ofthe wiper 51. The operators are thus immediately directed to idle linkconnectors and will employ plugs Gwhether such plugs are in the jacks oftelephone lines or upon the operators plug board.

While I have herein shown and particularly described the preferredembodiment of my invention I do not wish to be limited to the precisedetails of construction and circuit arrangement shown as changes mayreadily be made without departing from the spirit of the invention.

Having thus described my invention I claim as new and desire to secureby Letters Patent the following 1. A telephone exchange system includingtelephone lines extending to an exchange; link connectors at theexchange for uniting lines in conversation; calling line operatedoperators responsive devices at difi'erent operators positions; selectorswitches operable by calling lines for selecting responsive devices thatare free for selection; means for holding a succeeding or secondoperating responsive device hunting selector switch in position toconnect the same responsive device with the calling line operating suchsucceeding selector switch; and operator controlled means for freeingthe selected responsive device from the first selector switch andbringing it into connection with the second selector switch and therebywith the calling line operating the second selector switch.

2. A telephone exchange system including telephone lines extending to anexchange; link connectors at the exchange for uniting lines inconversation; operators telephones at different operators positions;selector switches operable by calling lines for selecting operatorstelephones that are free for selection; means for holding a succeedingor second operating operators telephone hunting selector switch inposition to connect the same operators telephone with the calling lineoperating such succeeding selector switch; and operator controlled meansfor freeing the selected operators telephone from the first selectorswitch and bringing it into connection with the second selector switchand thereby with the calling line operating the second selector switch.

3. A telephone exchange system including telephone lines extending to anexchange; a group of link connectors at the exchange adapted to the useof an operator for connecting calling and called lines; signal devicesfor the link connectors of said group and having controllingelectro-magnets; and means governed by equipment of the link connectorsfor causing said signal devices to operate when their link connectorsare idle and to energize said magnets to restore the signal devices whentheir link connectors are taken for use.

In witness whereof, I hereunto subscribe my name this 31st day of March,A. D., 1913.

MORTON L. JOHNSON.

lVitnesses:

G. L. CRAes, E. L. WHITE.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents. Washington, D. G.

